Recreational vehicles, including motor homes, fifth wheel trailers and travel trailers may be provided with an extendable slideout unit for increasing the vehicle's living space. This slideout unit may be extended for use when the vehicle is parked and is retracted in a telescoping manner when the vehicle is to be moved.
Prior vehicle slideout installations that include an extension/retraction system that relies on screws or a pinion for effecting telescoping movement of the slideout unit relative to the vehicle are known. Screws, in particular, must be short for practical reasons, including the tendency of a longer screw to deflect so that the axis of the screw is not absolutely straight. This, of course, greatly impairs operability of the screw. Pinions must also be comparatively short for practical reasons, including excessive weight in a pinion of greater length. Since the amplitude of movement of the slideout room or compartment can be no greater than the length of the screw or pinion, the amplitude of sliding movement, and hence the amount of additional space gained by the slideout compartment, is limited.
Other types of slideout installations for vehicles are also known. One such installation employs an endless cable that passes over one pair of pulleys supported by a main part of a mobile home and a second pair of pulleys mounted on side walls of an extension part of the mobile home to cause the extension part to reciprocate. Another slideout installation shows an expanding caravan, which also includes a rotatable shaft and two types of cables wound therearound. Rotation of the shaft in one direction causes one type of cable to wind as the other type unwinds, causing a sliding unit a second module to reciprocate in one direction (say outwardly) relative to first module. Rotation of the shaft in the opposite direction causes the second module to move in the opposite direction (say inwardly relative to the first module).
A challenge with slideable room assemblies is that a slideout room is cantilevered as it is extended. The outer end of the extended slideout room tends to tip downwardly. This puts weight on the slideout unit's operating mechanism. The cantilevered slideout room also tends to be loose at the top and tight at the bottom. This puts weight on the slideout mechanism, which in turn impairs slideability and also invites leakage.
Another challenge with presently known slideout units is that they require modification of the vehicle's underframe, unless the slideout unit is of small size. For example, it may sometimes be necessary to cut away a portion of the underframe in order to accommodate the operating mechanism of the slideout unit. This impairs the ability of the underframe to support the vehicle by lessening the strength and rigidity of the underframe.